Purification and some regulatory properties of glycogen synthase I from rabbit renal medulla.
1. Glycogen synthase I (activity ratio approximately equal to 1) was purified over 10,000-fold from rabbit renal medulla. 2. The purified synthase was stimulated about 1.5-fold by glucose-6-P and other divalent anions when assayed at pH 7.7 and near saturating UDPGlc. When assayed at physiological UDPGlc (75-100 microM), the enzyme was stimulated about 5-fold by glucose-6-P. 3. At pH 7.7 the activation by either Na2SO4 or glucose-6-P was due to an increase in V and a decrease in S0.5 for UDPGlc. At pH. 6.9, activation was due to a decrease in S0.5. 4. At low UDPGlc, synthase activity was inhibited by adenine nucleotides and the inhibition was partially relieved by glucose-6-P, UDP inhibited in a competitive manner with respect to UDPGlc. 5. These results suggest that the activity of renal medullary synthase I may be regulated by cellular metabolites.
D000818:Animals; D004789:Enzyme Activation; D019298:Glucose-6-Phosphate; D005958:Glucosephosphates / Q000494:pharmacology; D006006:Glycogen Synthase / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007679:Kidney Medulla / Q000201:enzymology*; D007700:Kinetics; D011817:Rabbits; D013431:Sulfates / Q000494:pharmacology; D014532:Uridine Diphosphate Glucose / Q000494:pharmacology
D005958:Glucosephosphates; D013431:Sulfates; D019298:Glucose-6-Phosphate; D006006:Glycogen Synthase; D014532:Uridine Diphosphate Glucose